Known in the art is a method of electroslag welding of light metals, consisting in successively mounting parts to be welded, with a desired gap therebetween, a forming device, and an electrode (USSR Inventor's Certificate No. 764,902). Following this, the gap between the edges to be welded is filled with a flux, leaving the electrode end extended over the flux surface, and a slag pool is set up. Then the welding current is switched on. As the volume of the slag pool increases, the bottom portion thereof is lowered while exposing new portions of the electrode for melting. In the process of welding the electrode is melted from above downwards, while liquid metal formed as a result of melting the electrode and the slag pool are kept within the gap. After the complete melting of the electrode and fusion of the edges of the parts to be welded, the welding current is disconnected. Metal is solidified within the gap thereby forming a weld.
A device for practicing this method comprises side moulds, a container disposed above the edges to be welded, and a container disposed under said edges. The upper container is defined by the side moulds and bars mounted on the parts to be welded. The lower container in defined by the side moulds and bars mounted under the parts to be welded. The lower container further comprises a tray retaining the flux and the weld pool within the gap.
The weld obtained by the prior art method with the use of the above device possesses insufficiently high performance properties due to incomplete degassing of the weld metal. In the utilization of the above device the setting of the slag pool is also impeded.
Known in the art is a halide-based flux (U.S. Pat. No. 3,585,343), containing in percent by weight:
______________________________________ potassium chloride 45 sodium chloride 27 cryolite (3NaF.AlF.sub.3) 22 lithium chloride 6 ______________________________________
Said flux makes it possible to carry out a stable process of electroslag welding, reduces well the oxide film on the welded parts. However, the weld obtained with the use of said flux in the process of welding, is porous and contains an increased amount of gases, thereby resulting in the sharp decrease in mechanical characteristics of welded joints.